This invention relates to the art of applying plastic foams to a substrate and, more particularly, to a nozzle extension assembly for a hand held foam spray gun.
It is of course well known to apply plastic foams, such as polyurethane foams, to a substrate through the use of a hand held foam spray gun such as the Model GX-7 spray gun available from the Gusmer Corporation of Lakewood, N.J. and the Probler spray gun available from Glas-Craft, Inc. of Indianapolis, Ind. Such spray guns include a nozzle assembly to which two liquid chemical components are preheated and pumped at high pressures for mixing and discharge from the nozzle component of the nozzle assembly to produce a plastic foam which is sprayed onto the substrate where the mixture cures in a matter of seconds. A hand operated trigger mechanism in the gun is operable to control the spray discharge and, in the aforementioned guns, air under pressure is supplied to the gun in response to actuation of the trigger mechanism to displace a valving rod so that the chemical components enter and are mixed in a mixing area in a nozzle assembly and then discharged in a spray pattern. In the GX-7 gun, the air is also operable to clean the pattern control disc in the nozzle component and to atomize oversize droplets upon ejection from the nozzle component, and in the Probler gun, the air is used to purge the nozzle component of chemicals following a spray discharge operation.
A considerable number of problems are attendant to the spray application of plastic foams to roof decks, walls, ceilings, and the like through the use of hand operated spray guns of the foregoing character. In particular in connection with the spray application of foams to roof decks, a major problem known as over-spray results from a combination of the distance between the gun nozzle or tip and the surface being sprayed and atmospheric conditions in the area of application. Over-spray results in the loss of foam material which does not get deposited on the roof surface but, rather, becomes airborne and spread over a considerable distance in the vicinity of the roofing project. This over-spray can result in the deposit of particulate foam material on cars, building walls, windows, landscaping and other surrounding structures which are not protected and which can be costly either to protect or to clean after the roofing project is completed.
A further problem in connection with the spray application of plastic foams to roof decks, walls, ceilings, or the like is the health hazard to a person or persons operating the spray guns. In this respect, the atomization of the spray material results in airborne contaminants in the area of application which are a health hazard to the person doing the spray application as well as other persons in the vicinity thereof in that, for example, the inhaling of the contaminants can lead to respiratory problems and/or the exposure of the person""s skin and/or eyes to the airborne contaminants can result in skin and/or eye irritation. Again, nearby workers and/or other persons not in the immediate work area are also exposed to the atomized contaminants because of the excessive amount of drifting of the atomized material resulting from the travel distance from the gun tip to the surface being sprayed. In order to reduce such drifting in connection with spraying foam on an underlying surface such as a roof deck, the gun operator must bend over so as to shorten the distance between the gun tip and the roof surface, whereby the operator is working in an uncomfortable position which promotes fatigue and, moreover, positions the operator""s hands and face closer to the surface which does not reduce the operator""s exposure to the atomized and airborne contaminants. It will be appreciated, of course, that fatigue results in decreased productivity.
In connection with the spray application of foams on vertical walls and/or ceilings, an operator often is required to stand on a ladder or other supporting structure in order to reach the upper extremities of a wall and/or ceiling, thus exposing the operator to potential injury should he or she fall from the supporting structure. Still further, in connection with the spray application of foams to substrates in general, the width of the application area is limited by the extent to which the gun operator can move his or her arm laterally with respect to the direction of the path along which the material is sprayed whereby, in connection with a given width of the surface to which the foam is being applied, multiple passes are required to complete the spray application process.
In accordance with the present invention, a spray gun nozzle extension assembly is provided by which an operator of a spray gun of the foregoing character can selectively use the latter with the nozzle assembly attached to the gun body or housing or with the nozzle assembly supported at a location spaced from the housing, whereby the operator can stand up and apply foam to a substrate with a desirably short distance between the nozzle tip and the surface being sprayed. More particularly in accordance with the invention, a spray gun nozzle extension assembly is provided which is selectively usable with an existing spray gun, whereby the latter can be used by an operator with the nozzle assembly directly attached to the gun housing or, alternatively, can be used with the nozzle assembly removed from the housing and supported at a location spaced therefrom by a support member having one end attached to the housing through the use of the fasteners for mounting the nozzle assembly thereto and having an opposite end to which the nozzle assembly as a unit can be attached through the use of similar fasteners. The nozzle assembly includes inlets for the two chemical components of the polyurethane foam, and the extension assembly includes a bracket attached to the gun housing and a pair of supply hoses having ends connected to the inlets of the nozzle assembly and ends supported by the bracket at the housing for connection with the source supply lines for the two chemical components. The nozzle extension assembly further includes an operating member between the trigger assembly in the gun housing and the nozzle assembly, whereby operation of the trigger by an operator holding the gun operates in the same manner to control the flow of the two components through the nozzle assembly as when the latter is directly mounted on the gun housing. Still further, the extension assembly includes an air flow line between the gun housing and the nozzle assembly at the outer end of the support member for supplying air in connection with the disc cleaning, atomizing and purging functions associated with operation of the gun.
Advantageously, an operator can mount the nozzle assembly of a gun at a location spaced from the normal mounting thereof, via the extension assembly, and apply foam to an underlying substrate such as a roof deck with a desirable spacing between the nozzle and deck surface without having to bend over, thus avoiding fatigue and other problems attendant to such physical stress. Further, the extension increases the width of deposit of foam along a path by about 50% compared to that obtainable with the nozzle assembly directly mounted on the gun body whereby, when multiple passes are required, the number of passes can be significantly reduced. Still further, with the nozzle assembly mounted on the gun body via the extension assembly, an operator can reach vertically high and/or overhead locations without having to stand on a ladder or the like, thus eliminating the danger of injury through a fall from the ladder. Preferably, the extension assembly provides for supporting the nozzle assembly at a location spaced 18 inches or 24 inches from the gun body, and selection between such dimensions, or other dimensions, provides versatility with respect to providing a desired comfort level for the gun operator during use of the spray gun depending on his or her height. In any event, it will be appreciated that the extension assembly provides for positioning the nozzle of the spray gun at a location relative to an underlying surface which minimizes over-spray and exposure of the operator to atomized material, thus to minimize drifting of the material onto objects and persons in the vicinity of the work area and exposure of the operator to potential health hazards from the chemicals in the atomized materials. All of the foregoing advantages promote increased productivity and promote a higher yield of materials used and improvement in material application.
It is accordingly an outstanding object of the present invention to provide a foam spray gun nozzle extension assembly enabling selective mounting of the nozzle of a foam spray gun directly on the gun housing or at a location spaced forwardly thereof for the mixing and dispensing of foam producing chemicals at the nozzle in response to actuation of the gun trigger on the gun housing.
Another object is the provision of a nozzle extension assembly of the foregoing character which, in connection with the spraying of foam on an underlying substrate, promotes a reduction in over-spray and drifting of atomized chemicals which are potentially hazardous.
A farther object is the provision of a nozzle extension assembly of the foregoing character which promotes a reduction in fatigue of a spray gun operator, an increase in productivity and a higher yield with respect to the sprayed material.
Still a further object is a provision of a nozzle extension assembly of the foregoing character which promotes a reduction of exposure of workers to potentially hazardous chemicals.
Yet another object is the provision of a nozzle extension assembly of the foregoing character by which a foam spray gun is selectively operable with the nozzle on the gun housing or supported a location spaced from the housing and wherein the extension is mountable on the housing through the mounting components for the nozzle and wherein the nozzle is mounted on the extension through like fastening components.
Still another object is the provision of a nozzle extension assembly of the foregoing character which is structurally simple, economical to produce and which provides for the easy and quick conversion of a foam spray gun between gun assemblies in which the nozzle is mounted directly on the gun housing or at a location spaced therefrom.